Impact clutch



April 6, 1948. F. P. FORSS IIPACT CLUTCH Filed April 23, 1943 r h I 4INVENTOR. fk/r/r/ar fans PatentEd Apr. 6, 1948 IMPACT cmrron Frithiof P.Forss, Aurora, nlqfassigliortolnde pendent Pneumatic 1 Tool 1 Company,Chloe 11]., a corporation of Delaware L Application April 23, 1943,Serial;No. 84

16 Claims. (01.19%31015)? This invention relates to portable poweroperated impact wrenches for screwing up and unscrewing nut andbolts bypower.

The invention, while relating to tools of the character referred to, isparticularly concerned with the impact clutch mechanism employed in suchtools for delivering a series or succession of rapid and relativelypowerful rotational hammer blows on the anvil member of the clutch totighten the nut or bolt after it has been set or to loosen a tight nutor bolt on removing the same, the invention having among its principalobjects the following:

To provide an impact clutch of the roller type,

that is. wherein the impact elements are in the form of solid,relatively long, heavy metal rollers freely mounted in recesses in thehammer member of the clutch" for movement into and out of clutchingengagement with the jaw or abutments on the anvil member for impartingrotation thereto in the operation of the clutch;

To locate the roller elements wholly within the recesses and in slidingcontact with the end walls thereof and provided with tapered oppositeends to prevent the extremities of the rollers striking the abutments ontilting of the roller elements in the recesses; and

To provide a flexible driving connection between the rotary driver forthe clutch and the hammer member of a character whereby the impact ofthe roller elements on the hammer member on releasing the abutments willrotate the hammer member ahead of the driver to absorb such impacts byovercoming the inertia of the hammer member to prevent premature wear onthe hammer member and the recoil of the roller elements against theanvil member.

ically operated impact wrench hich the motor section I of thetoolfoccupying he upper half portion of the machiiie'is' boltedorotherwise rigidly secured in axial alinernent to the clutch containingsection 2 'whicnoccupiesf the lower half portion of the toolIfThemotorfsection I has aside or other handl'eiethrpugh'which compressed airis 'suppliedtothe tool'idroperating the tool motor. The

handle 3fl'iasafltting 4 at itsouter end forconnec'tioiiwithanairsupplyhose (not shown) as in tools'ofthischaracter.V The handle {mounts a throttle valve, jalsol not shown, which by atrigger '5 in thehandle Enables the operator handling thetoolltofcontrolthesupply of motive fluid thereto.

1Inthe'toolshown'the motor is of the rotary shaft ecti type haviri bladeprovid ed rotor 6, the lower I 1 9 which extends into the upper endfd,theiclutchjsection 2 for driving the hammer membe 8, f the clutchthrough a flexible drive to beilaterf described. p

'Thefjoutsidef casing! of the clutch section 2 houses and'niountsthe'operative'mechanism of theclutch and provides a journal for thespindleflllfatj the lower end of the hollow cylindric v anvil-member lo: the clutch. The anvil member l lifreceiveaithe'hammer member 81 inconcentricfrelatioii"within itsouter surrounding annulai wall l2. andwhich wall member is provided with a] pair" of diametrically disposed,inwardly -*extending. radial 'abutments orshoulders l3, l3.

Tiiese"abutments 13 are integral with the anvil walllzand extend axiallythereof as indicatedin The invention consists further in the features Ihereinafter described and claimed. In the accompanying drawings- Fig. 1is a side elevational view with parts broken away and in longitudinalsection of an impact wrench embodying a clutch construction of myinvention;

dotted lines; in Fig.1. The wall member l2 between thelab utments I3 isformed with arcuate track-ways Hillier the impact roller elements 15,!def the clutch to be presently described. 'lheftrackways'ji l -am madeon a radiusslightly greater thanthatpf thehammer member 8 to provideclearance spaces therebetween for centrifugalfprceftojmove the rollerelements l5 into the Qtrachvvays toengage the abutments l3 as showninligsfl and 4. This positions the roller elements "l5f or."clutching theanvil and the ham..

mer members 'for rotation in unison when running afree nutprboltjand fordelivering a series or Fig. 3 is a similar sectional view taken on line3-3 of Fig. 1 to illustrate the flexible driv between the tool motor andthe hammer member of the clutch; and

Fig. 4 is a sectional view similar to that of Fig. 2 showing the rollerelements in the track-ways approaching the anvil abutments.

In the accompanying drawings. I have shown a uccessions: rotationalhammer blows on the abutments wl'ieiith'e "anvil member is held againstrotationby thenut'orbolt. i

Th toner-elements li engage and/or strike ag instjtn*dppdsite sme edgesis, .Il6a of the side edg'es being on arcs of the v s the rollerelements. Inthese rek "is'poii'itd out that the tool motor 6 is of thereversible type, the roller elements l5 I strike against the side edgesof the abutments as fOr example at the points A in Fig. 2, the lugs 39,40 of the drive are in solid driving engagement as will be apparent fromFig. 3 wherein the arrow a indicates the direction 01' rotation. Theresultant action of this impact of the roller elements on the abutmentsforces the roller. elements towards the opposed leading side walls 4| ofthe recesses I9 along a line indicated by the arrowB in Fig. 2. Theroller elements l5 would strike with considerable force against theleading side walls 4| at the points 6 if the hammer member at thismoment were directly conwould also rebound from these solid blows andstrike against the abutments on the surfaces Ill as at points D causingwear. With the spacing between the lugs 39, 40, the impacts at 0 forcethe hammer member ahead of the driver 35 and these impacts are absorbedin overcoming the inertiaof the hammer member in throwing it ahead ofthe driver. Hence, the roller elements may be madeto strike relativelypowerful blows and respond quickly to the speed of the motor as the lugsclose into driving engagement.

The machine shown and described has been designed tohave the minimumnumber of parts for the striking mechanism, large striking surfaces forthe rollers with no adjustments required. The parts are all of a heavymetal construction and are rigidly clamped together providing aneffective impact tool.

The details of construction and arrangement of parts shown and describedmay be variously changed and modified without departing from the spiritand-scope of my invention, except as pointed out in the annexed claims.

I claim as my invention:

1. An impact clutch of the character described comprising, relativelyrotatable hammer and anvil members, the anvil member having a wallsurrounding the hammer member and provided with internal abutments andtrack-ways there'- between, roller elements carried by the hammer memberin recesses therein and movable by centrifugal force into the track-waysfor delivering a series of rotational hammer blows on the abutments inthe rotation of the hammer member relatively to the anvil, said hammermember providing side and end walls for the recesses for retaining theroller elements in operative position therein, said roller elementsfitting wholly between the end walls of the recesses and having theiropposite ends in sliding contact therewith, and means for rotating thehammer member.

2. An impact clutch of the character described comprising, relativelyrotatable hammer and anvil members, the anvil member having a wallsurrounding the hammer member and provided with internal abutments andtrack-ways therebetween, roller elements carried by the hammer member inrecesses therein and movable by centrifugal force into the track-waysfor delivering a series of rotational hammer blows on the abutments inthe rotation of the hammer member relatively to the anvil, said hammermember provlding side and end walls for the recesses for retaining theroller elements in operative position therein, said roller elementsfitting wholly between the end walls of the recesses and having theiropposite ends flattened and in sliding contact therewith, and means forrotating the hammer member.

3. An impact clutch of the character described nected with the driver 35causing premature wear 'at the points of impact. The roller elements .7r comprising, relatively rotatable hammer and anvil members, the anvilmember having a wall surrounding the hammer member and provided withinternal abutments and track-ways therebetween, roller elements carriedby the hammer member within recesses therein and movable by centrifugalforce outwardly of the recesses into the track ways for delivering a.series of rotational hammer blows onthe abutments in the rotation of thehammer member relatively to the anvil, said hammer member providing therecesses with divergent side walls and end walls for anvil members, theanvil member having a wall surrounding the hammer member and Providedwith internal abutments and track-ways therebetween, roller elementscarried by the hammer member in recesses therein and movable bycentrifugal force into the track-ways for delivering a series ofrotational hammer blows on the abutments in the rotation of the hammermember relatively tothe anvil, said trackways being in arcuate form on aradius slightly greater than the radius of the hammer member and saidabutments having blow receiving surfaces on the opposite sides thereofto receive impacts from the roller elements in either direction ofrotation of the hammer member, said hammer member providing side and endwalls for the recesses for -re-- taining the roller elements. inoperative position therein, said roller elements fitting wholly betweenthe end walls of the recesses and having their opposite ends in slidingcontact therewith, and means. .for reversely rotating the hammer member.

5. An impact clutch of the character described comprising, relativelyrotatable hammer and anvil members, the anvil member having a wallsurrounding the hammer member and provided with internal abutments andtrack-Ways therebetween, roller elements carried by the hammer member inrecesses therein and movable by centrifugal force into the track-waysfor delivering a series of rotational hammer blows on the abutments inthe rotation of the hammer member relatively to the anvil, said hammermember providing side and end wallsfor the recesses for retaining theroller elements in operative position I ments interposed therebetweenfor clutching and I declutching said members, said roller elements beingSlidably mounted at their ends in recesses in one of said members,saidroller elements hav-' ing their opposite ends tapered to prevent their 7dun t lr edlllfll. fornnpuflngmhfluntn llninpletdulflnotthednnetermibedrelatively rotatable III-nerand mmmmcab mwnmmemuun memfiu'. meets for mthe driver.

emmmdmurmemmed mm withinmmllghufmmtsendhut-nmithere- 11..Anhnpmtdutehofitherhermfierdesrribed rehflwelymhhflehnmmer andmshoulders mm; lateral mmm mmm sur'-- 15 faces extending mummy from saidtrack-ways,

rdler demm'ls remhbly carried W the hammermemba'mradialrmmtheremandmwamIn response to emh'flml force mm the hack-nus inmm: a series ofrotatinnml ,lnmmerhbwsmthemmwematfihehteraltbnotthehammernmherremflivelywflm mllnmbeandmelnsfm-mmrmgthehammermunber.

' lzhnnnpeetclutchoflfiechmranterdescnmmll'lslngrellflmlyrdlhhrehammerandi arm-- wfl members, the vmmvim memberhaving a walm the hnmmermmber and provided. with internal Mill-Hilts andtrack-ways there:-

mmmmmmwmmmm mmmmgmmmmmm mmumywm munbuinmthudnmflmnhlebyemmm shuuldershaving lateral impact: receiving mines extending mm from the track-wag,roller elemmfs xewomhly carried by the: hammer member in radial recessesand mmbre:

wm imdelivering a series @fi mtati'nnarhammerbhwsomthesmuwersmtzthehflerallimpletremiwingmmmesflmrmfimfiherotafiomof the hammer member w the anvil. 5 member, mid hammer mm and means re--nimble therewith pruwmmg and end walls; furaidmforniainmgfihemflerdementia inoperativepmiiilntliereimsmidmner elements:mgwhollybewemtheemilwmflsorthew thehnnmn-munhanllmfwmthe driver.

I. Inanmmctlnoldthemdenalbed mm 5. vi] when, the anvil .w

faces at! end 11%, and means Eur rotating me ham, met member. v

13. An Imp-at clutch of the character described 7.1a 2L wallsurrumdingthe hammer member and provided with internal abwnemrs amflltrack-ms slid ahlflmentts relatively ahrumxtr shuulders lmwirng lateralimpact; receiving: sur- "1:. mnrdilly firum said trunk-waysaheeddfllemM-h-Mtbemhmmin: the inertia! the-hem number.

openflvepasiziomthamsardmfler eiemerrtsfltflnewholwmwemtheendwmflsofthem- "mandhavmgtheiromasiteendsrelatiwelyelnnetoummdwalmsfmslidablemmem;

" therewith, Mannheim-infirm; the member.

m Idem, xemsflrm. Me hamfilflncmfidgleempmzlwmemedhnbdwemthednlw-lndthemu'eimm hmrmbermd pact receiving surfacesthereof in either direction of rotation of. the hammer member relativelyto the anvil member, and means for rotating the hammer member in eitherdirection.

15. An impact clutch of the character described comprising, hammer andanvil members relatively rotatable about a common axis, said anvilmember having relatively abrupt impact receiving surfaces, elongatedroller elements rotatable with the hammer member and centrifugally urgedinto impacting relation with said impact receiving surfaces on rotationof the hammer member, said hammer member having driving surfacesfordriving the roller elements, said driving and impact receiving surfacesbeing substantially co-extensive in length with the peripheral portionsof the roller elements driven by the hammer member against the impactreceiving surfaces in the rotation of the hammer member relatively tothe anvil for imparting rotational hammer blows thereto, and means forrotating the hammer member.

16. An impact clutch of the character described comprising, hammer andanvil members relatively rotatable about a common axis, said anvilmember having relatively abrupt impact receiving surfaces, elongatedroller elements revolvably carried by the hammer member in radialrecesses therein and centrifugally urged into impacting relation withthe impact receiving surfaces on the rotation of the hammer member, saidrecesses receiving the whole of the roller elements and having wallportions forming driving surfaces for the roller elements, said drivingand impact surfaces being substantially coextensive in length with eachother and with said roller elements and engageable with the peripheralportions thereof for the major portion of their'length for impartingrotational hammer V blows against the anvil men her for rotating thesame on the rotation of the hammer member relative to the anvil member,and means to rotating the hammer member.

FRITHIOF P. FORSSf REFERENCES CITED The following references are ofrecord in the file of this patent:

UNITED STATES PATEN'I S Shafl! -,.-Q Mar. 7, 1944 I

